Livestock Studies 2014, Vol 54, Num, 1     (Pages: 008-014)

Determination of genetic and environmental factors affecting growth curve and sire evaluation with the aspect of curve parameters in Pirlak lambs I. Effects of some environmental factors on nonlinear growth curves in live weight


1 Afyon Kocatepe Üniversitesi, Veteriner Fakültesi, Zootekni Anabilim Dalı, Afyonkarahisar - Factor affecting growth curves of 328 Pirlak lambs born at Afyon Kocatepe University Research and Application Center in 2008 and 2009 were investigated. Different nonlinear mathematical models were fitted to live weight data of lambs from birth to yearling. For this purpose Bertalanffy, Brody, Gompertz and Logistic models were compared. The best fitted model was Brody (%95.58) followed by Bertalanffy (%95.17), Gompertz, (%95.00) and Logistic (%94.20) models. The effects of birth year, birth month, birth type, gender and age were significant (P<0.05). Contradistinctions of mature weight and rate of maturing between males and females indicated that later maturing ram lambs will have heavier mature weights than ewe lambs. Using adjusted data for the significant factors will also be useful in a selection program. Keywords : Growth curve, sheep, pirlak